Otto was Duke of Swabia in 973 and Duke of Bavaria in 975 {ref.: "Royal Ancestors of Magna Charta Barons," Carr P.
Collins, Jr., Dallas, 1959, p. 236, source for this line; a differing ancestry is given by W.H.Turton, "The Plantagenet
Ancestry" (Balt.:Gen.Pub.Co.,1968),p.181,q.v.}